Convex and Concave Lenses


Convex and Concave Lenses

Convex lenses are thicker in the middle than the edges. These lenses bulge in the middle like a football. When light rays pass through a convex lens, the rays are refracted so that they come together at a point behind the lens (This point is called the focal point). A camera uses a convex lens to focus the light rays. Microscopes and telescopes also have convex lenses in them. A magnifying glass is a convex lens. People who do not see nearby things well may wear eyeglasses with convex lenses. If you look through a convex lens at a close object, it will look bigger.

Concave lenses are thinner in the middle than at the edges. When light rays pass through a concave lens, the rays do not come together at a focal point. Instead, they are bent and spread apart as they pass through the lens. People who who do not see distant things clearly may wear glasses with concave lenses.


A lens is a smoothly curved piece of glass or plastic. Light is refracted when it passes from air into clear glass or plastic. Because of this property, we use glass and plastic to make lenses. Lenses refract light in a special way.



1. What electronics use convex lenses?

2. When people can't see distant things clearly, what type of lens do they use?

3. What type of lens does a camera, microscope, and telescope use?

A. Concave Lenses B. Clear Lenses

C. Convex Lenses D. Regular Lenses